Differential



E. o. DoAK 'Find sept. 1v. 1924 Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.-

EGBERT o. Dom, or CANIsToTA,`soUTHDAKOTA;

DIFFERENTIAL. v

Application filed September 17, 1924. Serial No. 728,124.-

To all whom t may concern.:

Be it kno-wn that I, EGBERT O. Donn, a

citizen of the UnitedStates, and aresident .i

plish the object of allowing varying ratios of speed between the rearwheels of a car when being driven in a circular path, but which willeliminate the possibility of one wheel remaining stationary while theother is driven forwardat a doubled rate of speed.

Stated in another way, my invention contemplates the positive drivingof, both rear wheels lof a car at a definite speed deter- ,mined' by thepropeller shaft-velocity, the varying ration of speeds between the.frear wheels being vaccomplished by vallowing either of the wheels toidle aheadat a rate faster than the rate of rotation positivelycommunicated from the propeller'shaft.

VA further Objectis to provide means for positively transmitting thepower .from the propeller shaft to the rear axlesl of a car in eitherforward or reversed direction, which will yet allow the rear axleshaftsto difterential in either forward or reverse directions ofrotation. n l. l

' More specifically, referring to the latter object, itis my aim toprovide two series of power-transmitting links adapted to selectivelylconnect the propelling mechanism with the driven axles so as topositively transmit power to the axles in the direction of rotation ofthe propelling mechanism, and simultaneously to allow fasterrotation'iofeither driven axle, either series yof powertransmitting links beingmovable into 'operative positionv automatically lby the rota-v tionofthe propellingmechanism in the direction in whichthe` particularseriesy is adapted to positively transmit rotation, the other seriesbeing .simultaneously moved out of operative position by the samefactor.

A still further object is to provide actuating meansfor accomplishingthe above object, controlled* by the retarding resistance to rota-tionof the driven axles.

Another objectv is to provide such an actuatingmeans which is controlledby frictional engagementV betweenv the ends of. the axles. f I i .Withthesel and other objects vin view, my invention consistsA inA theconstructon',fa1f

rangement and. combination of. the various parts of mydevice,wlierebythe'objects contemplated are attained, as hereinaftermore fully set forth, pointed out innmygclaims accompanying drawandillustrated in the ings,'in which: i.

Fig. ,l is a horizontal, sectional view through the rear axle,differential andpro vpeller l shaft housingy in an automotive. ve'hiele, illustrating ,myy invention in plan, a

portiony of thecasing being broken away in order to better illustratethe parts. i.

Fig. y2 is a detail, vertical, longitudinal, sectional. View throughthey differential mechanism, taken onthe line 2-2 ofFig.L1.

Fig. i 3 is al vertical, l transverse,y sectional 1:1

view, taken on the line 3-f3f ofFig., 2. Fig. 4 is a perspective ,viewof ,a pairof power-transmitting links. i i I Fig; 5 is an enlarged,diagrammatic, figure. illustrating ,the construction and` arrangement-of the power-transmittinglink and ratchet Wheel relative to each other.

Fig. 6 is a sectionalview,` similar Vto Fig.

3, of a slightly modifie-d form of my inveni tion.

, A'A defect that is. inherent in the ordinary differential mechanism inuse on. cars is that one of the rear wheels of thecarmay become stuckand secured against rotation, and the power will contine tovbetransmitted to the other wheel alone, which will spin at a speed doublethe normal speed of the rear Wheels relative to the propeller shaftspeed. My invention is primarily designed top eliminate this objectionbyproviding a posi-' tive driving connectionbetween the."propel lershaft and each of the rear axle shaft-s.

I have used the reference characterv 410 'to indicate the comb-ined rearaxle and differential housing, which isof the ordinary con- To it is4bolted the vpropeller struction. shaft housing 1l, in the rear end, ofwhich is rotatably `mounted in roller bearings, 12, the driving pinion,13. l

. The rear axle shafts, 14, are journaled at 60 'hubs, 22, ot theratchetwheels.

vlto gears which form part Vot the lditle'refntial mechanism.

In nay-invention these gears are-removed Vand in their place aresubstituted the ratchet `wheels, 19, which afre'lkey'ed to the Vshaft inthe same manner and held against longitudinal movement by thesame rings,20, vused in the'old construction.

yIt may be mentioned here that thefteeth, '21,'ot` the ratchet wheelsare square in crossseCtiOn, as illustrated inFigs. 3 andv5. 'The purposeof this construction will later be more fully explained.

The hubs, 22, of the ratchetf'wheels, i9, are slightly reduc-ed so as toiorm 'the shoulders, 23.` Y

The differential mechanism is ysupported in a housing, composed ofvthering gear, 24, vand the end plate, 25, which are, provided withcentral circular openings th-rough whichv the hubs, 22,of the ratchetsproject.

"Iliev'members, 24 and 25, are secured'together at the periphery ot theplate, A25, bythe arched plates, 26. `Screws, 27, received throughopenings in the members, v24 and 25, and threaded into the plates, 26are used for this purpose. 'Vhen assembled, the members, 24 and '25,snugly engage the vshoulders, 23, of the ratchet wheels, 19, in

order toV secure them against outward movement. ,Y y

I provide the llanged sleeves, 28, which, engaged between theinwardly-extending bearing-retaining sleeves, .29, of the casing, '10,'through the medium of the 'friction washers, v30; andthe outer facesofthe members, 24' and 25, respectively, serve to position Vthe'differential mechanism when ythe yhalves 'of the housing, 10, aresecured "to- V'gether, and 'to maintain 'the vengagement of Lthe teeth,31, of the ring gear, 24, with the pinion, 13. It`will be understoodthat the ltriction washers, 30 are of the, ordinary construct-ion. L' yIt'willnow be seen that the unit V,comprising the members, y24, 25 and26 is rotatably mounted relative to the. shatts,"'l4, on the to transmitrotation trom "this unitto the ratc'hets, Ipro'vi-jde the pairs otpawls, 32, which are pivotally mounted on '.bolts, v33, supportedbetween the members, 24 and 25, respectively. In the form ot'myinvention illustrated herewith, I have shown `three In order of suchpairs of pawls equi-distantly spaced around each ot the ratchets, 19. Itwill be understood that mo-re 'or less might be utilized, :but I findthat three or tour pairs prove the most practical.

Referring to Fig-4 it will be noted that `the'free end of each p'awl isenlarged so "as to occupy the entire width ot the space in which thepivoted shanks, 34, ot thev pawls are-confined. Thewidth of theseengaging teeth, 35, is the same as the width ot the teeth, 21, of theratchets. 'Thus I- obtain a maximum ot strength in a minimum ot`ALspace,- the outer-portions for the pawls which `be allowed to'engagethe ratchets at one time. In order to control this yengagement ofthefpawls I provide the following mechf 4anis-m.

Between the inner 'endsot the vratchets,'19, fand rotatably mounted onthe inner' ends ot vthe axle shafts, 14, by means `ot the hub,

' 36, is a 1disk,'37, which separates thepawls Vengaged with one ratchetfrom those 'engagedwith the other. (The hub, 36, extendsV vin eitherdirection from the fdisk, '37, and is lrotatably received within ftherat'chets, 19, which are provided with enlarged bores tor that pur oose.Betweenthe edges ot'the hub, 36, an 'the shoulders, 38,1tormed "by thevenlarged 'bo-re and received `with-in said bore, are the springs, 39which are fot relatively heavy material. The'objectfottf-these springsis to 'provide a resilient, friction-al connection between the'ratchets, 19,and the plate, 37, so that when the direction of rotationot' the pawl, 24, is reversed this triction will retard the rotation otthe'plate,l37,

in the new direction. This retarding action shifts 'the pawls, 32, intoVthe positionrequired vbythe change in rotation, as will now beexplained. f

Pins, 40, aresecurely mounted in the plate,

.37, 'extending from either side thereof, and

arereceived'between the pawls, 3201i each pair. Springs, 41, maintainthe Vengagement ot the pawls, 32, with the pins, 40, tending to drawthepawls =toward' learch other.

Shouldered bolts, 42,- l'secured to fthe "memb.ers,24 and 25,respectively, pass throughY ring gear, 24. "The-bo`lts, 42, also serveas a bracing means fto space fthefmemleers, 24 and 25, vapa-rt inaddition to'- the plates, '26.

vrslots, 43, in the plat-e, 37, and :serve to `v limit the 'movement' of'the 'plate relative to the l The bolts, 42,vr may be dispensed with' asfark CII as their function in f limiting vthe movement of the plate, 37,is concerned, and thebolts, 33, 'allowed tol performthat function. Amodified form in which this is accomplished isillustrated in Fig. 6, inwhich the plate, has formed on its `periphery a pair of spaced lugs, 44,the path of 'which is intercepted by the bolt, 33.

Referring nowy to the operation-of the device and: for illustrationto'Fig. 3, it `will be assumed that the ring gear, 24, is rotating inthe direction indicated by the arrow, A45.

The force opposed to the pulling power of the propelling meanslwhichtends to retard the rotation of the shafts,1l4, and ratchets,19,'frictionally operating upon lthe plate, 37, through the medium ofthe springs, 39, will maintain the plate, 37,-in the position shown y inFig. 3.l In this-positionv the pins, 40, being positioned a little tothe rear ofthe bolts, 33, 'in thedirection of rotation,"\vill maintain'one ofthe pawls of each pair out of engagement with the ratchets, 19.

Forv convenience' inl describing vthe operation, I will referto thisseries of' pawls, `which is inoperative when the ratchet is being drivenforward', as they pawls, B, and the lother series as the pawls, A.

At the same time lthe pawls, A, will be allowed to remain in engagementwith the ratchet wheels, and will transmit positively 'the rotation ofthe gear, 24 to the ratchet wheels. In going around a corner the wheelon the outside,` traveling through a rlarger arc, will becaused torotate at a rate faster than that ofthe wheel on the inside; carwill'thenbe driven entirely from the inner wheel, and the outerwheel'will idle forward at the proper speed, the ratchet on theoutershaft being allowed'v thus to rotate by the pawls,-A. It will benoted that when this occurs the rotational friction against the plate,37, of the two ratchets, instead of being inthe same direction' will bein opposite directions, the two forces tending to neutralize each other.I-Iowevenin addition to the retarding force exerted by the ratchet onthe vaxle which is driving the car, my device provides an `additionalfactor tending to maintain the plate, 37. in its initial position.

Referring now to Fig. 5, it will be noted Vthat the face `ofthe ratchettooth., 21, is inclined toward-the bolt, 33, within the arc of movementVof each of the teeth, 35, as indicated by the broken line, 46. Thus anytendency of the pawl, 32, to disengage itself from the ratchet would latthe same time'tend to f orce the ratchet ahead against its resistance torotation. vSince this force is considerable, it will be seen that thep-awls 32.

"will be `securely locked in position and will thus retain' the plate,37V against this unwanted movement.

Assuming that the car is still `moving for- The driven forwardpositively, thus rotating the ratchets, 19,1 forwardly relative tof thering gear, 24. The frictionalk engagement ofthe ratchet-s will lalsocarry the plate, 37,'-in`the direction'indicated by the arrow, 47, untilthe slot, 43, limits'the 'motion of the plate relative to the ringgear.l This `forward irotation of the plate carries the pawls, A, out ofengagement with the ratchets and lowers the pawls, B, to position where.the' forward rotation of the ratchets will, through the pawls, B,transmit rotation to the-ring gear, 24, in order to drivethe engineforwardly.

When the' driver yshifts gears l and l causes the propeller shaft toroitate in a reverse direction,`the same operationis effected'as thatjust described. -The `ring gear' rotates rearwardly andthe plate, A37,is lheldv against ,y

rotationby the frictionalresistance ofthe ratchetsV It will-be seenthat-the` samedif ferential action ywill take place- 'in driving theVcar around a ycurve backward asin driving forward around vra corner.Some 'changes may be made in the-construction and arrangement ofythexparftsfof my invent-ion'withont departing vfrom lthe real spiritand'purpose of my invention, and it' is'my intention to coverby-.myclaimsfany modifiedformsVr of structureor use ofmechanical"equivalent`s which may be' reasoni ably included within theirscope.V -I claim-'as my invention: 'Y

' l.`In, a differential, driven elements and a` driving element,the`latter carrying two series, oppositely disposed, of power transmittinglinks movable alternately' to positions for rotating the driven-elementin either direction, and means ycontrolled-by the reta'rding resistanceto rotation of the drivenelements, for simultaneously moving one seriesof links to operative, and the other series to inoperative position,said 'means includinga single :plate frictionally engaged between thedriven elements, and projections 'carried by the plate enga-ged with the`links the power transmitting links being arranged Vto resist fdisengagement fromy the ldriven element when in engagement therewith.

2. lIn a differential, driven elements l'and al driving element,th'e'latter carrying t'wo series, oppositely disposed, ofpower trans-Vno V Y of an automotive-vehicle, a pair of vratchet wheels on they@abutting y.endszyoi said axles, a plurality of pairs yof pawls,oppositejly directed-and engageable with the.ratchets,eacn Apair.being`pivoted onfa single stud ycarried by adriving element, a pla-tefrictionally engagedbet-ween' the ratchet wheels and cars fryingaplurality of projections each .projecftionlbeing engaged :between-@thepaWls and in lcontact `with. each pawl of its respective paarfand-,adapted to retain ione pawl of each pair -`out of engagement-Withtheragtchet :wh-eels. y f' Y 4.7111 combination:Withthe driven axles voivan automotive vehicle, a-pair of ratchet wheels .0n fthe abutting,endsof said aXles, .afpl-urality offpairs of vpa-wls, loppositelj)7 di-Arected, .fpivoted cna driving element, and .engageable with theratchets,and means ac- `.tuateolfbynotation of the driving element ineither direction, Afor bringing into -operative .engagement iwith l theratchet wheels, the gpawlsfdirected to rotate the axles inv thatv-cl'iirection, -saidmeans including a plate' having a hub rotatablyamountedv on the abutting ends ofthe axles, :the ratchet Wheels be-,jing recessed to receive the rends-of the fhub,

and .coil springssurrounding the axles and engaged between the wheelsand Vthe hub.

5. In a'diflferential, in combinationvvith zthe driven axles ofanrautomotive vehicle, .a pair .of ratchet Wheels on the abuttingA endsof. saidfaXle-s, ay driving element,` including ,spaced iside1nembers,-shafts connecting said side members, .a friction platerotatably -vmounted ontheabutti-nglends of the shafts .and friction allyengaged between sai'd ratchet wheelsa series .of vpairs ofopposlitelyvdisposedpawls .mounted on the shafts l.oneither side of saidplate, the plateserving sto rsepa-rate..the,series of pai-rs on onersidefrom .thatonthe other, and l.means carried by 7the'` plate to bring intoengagement 'with the ratchet wheels, the `gpawls j directed -to trans.-.mit rotation in the direction.otrotatiofn or' the drivingyelgement. Y

.. In a differential, Yin combination with ythe driven .axles -of .anautomotive vehicle, avipair ofratchet Wheelsjon the abutting ends4ofgsaid axlesra'drivi-ng element, including ,spaced side members,lshafts Vconnecting said .side members, a friction plate ,rotatably,mounted lion. the abutting .ends of the' shafts ,and `4frictionally iengaged between ysaid `ratchet,vw\v*-lieels, .a series of pairs ofoppol-sitelv ,disposed pawls-1nountedon the shafts Qn either side hofsaid :plate'fthe pla-te serving -to .separate/thesseries'of pa-irs onone side madera fromthatxonntlae other, thetwo paavlsfof each pairheingWidenedat their 'l-lfglgllg ends-so kas :to ouerelieeacliotherfand meanscarried by the plateto bring into l.engagement with the ratchetv'wheelsthe pawls directed -to transmitrotation in the :direction of rotation ofthe! driving -.element.

7. 11i-a fditfereigitial, -in*combinatiolglwith the driven axles of .anautomotive vlehiielafa of. each pai-r, and studs-extendingthnough theplateY andieififgaging each pawliof 'the ref .spectiver pairs, :sa-idstuds being-.disposed fbetween the pawls and the springs.

F8. In a differential, in combination Vwith the driven axles ofanautomotive vehicle, a pair of ratchet wheels fon vtheabutting; ends ofsaid axles provided avidi/annular' recesses, fa friction-plate havingafhubrotatabl-y mounted @on the :ends @of the ax-les `and enclosed in@the recessed portions Ioit' the ratchet avheels, Acoil springs (engagedbetween the ratchet wheels and fthe ends of the'-;l1ub,

.in said recesses, the Iratchetwheels lbeing provided with' reducedhubs, a Vdriving ele,- ment including two .side gmembersxj o ur-nalledon said reduced'hubsf-,and engaged fagainst the sides off the.ratchet-wheele shayftswcoin necting the two side members, a seriespairs lof @ogpfpositely disposed paiwls -piafoted .on the f shafts,one-it'her si de `oit the plate,- lthe `plate servi-ng to-ispaee the twoseries apart,

springs connect-in-gtthzfe twof pawls of each jecting between 'thesprings and ipaW-,ls lof .each pair, engaging :each pawl of each-pair.

v9. Ina differential, in combination Vwith -the driven axles vofa-n-,aa1tornoti.ve vehicle,-a pair of ra-tchets .mounted Afon ftheyabutting ends of the axles, a relatively thinirietion.diskrotat-ablyimounted onthe abutting ends of the aXlesza/nd receivedbetween ithe spa-ced sides of theeratchets, a driving member,.gal.series fof pairs of 'oppositeliy disposed pawls pivoted4 on .thedriving member onffeit-ner side .of the plate, the .twopawls ofeacllfPair .being `:connected by ,tension springe-studs carried .by lvthe.plate `and projecting in either direction, .the ',respecti'veqends ofeach ;.stud being-engaged between the pawls and sprgigng respectivelyiofthe adjacentvpaiyrsfand .simultaneously engaging eachpawlof therespective pairs, the pawlsbeing .fplovided ldisposed inthe/planesvseparating the pawls With engaging ends engage-able with the ratchetteeth, the ratchet teeth being inclined toward the shafts and Within thearcs of swing ot' t-he engaging ends of the paWls.

l0. In combination with the driven aXles of an automotive vehicle, apair ot ratchets mounted on the abutting ends of the axles, and havingreduced hubs, a driving member comprising a pair of side elementsrotatably mounted on said hubs, casing members removably connecting saidside elements in positions engaging the faces of the ratchets, theratchets being recessed on their inner faces next to the axles, afriction disk engaged between the opposed faces of the ratchets andhaving a hub rotatably mounted on the axles landreceived Within therecessed portions of the ratchets, a series of pairs of oppositelydisposed paWls `pivoted on the driving member on either side of the diskand engageable with the ratchets, and Y

